A pressure accumulator known from WO 2013/056834 A1 has at least one accumulator housing with at least one connection for a pressurizing medium, in particular in the form of a fluid, which fluid can be stored in the accumulator housing. A filling material is at least partially introduced into the accumulator housing and has cavities or forms at least one cavity for the at least partial receiving of this pressurizing medium. The inside of the accumulator housing is fully filled with the filling material, so that the filling material is in full-surface contact with a wall of the accumulator housing.
If, in the known solution, the filling material is formed as foam, in particular polyurethane foam, thickness differences in the foam material can be generated by multiple injections or applications of foam. It is then advantageously possible to obtain a gradient-type structure of the foam material such that a very thick material is used on the inlet side of the accumulator. That material then changes in the direction of the opposite side of the accumulator housing with increasingly open pores or with lesser thickness. At the point of entry of the pressurizing medium into the accumulator housing body, an increased resistance can then be built up in that the barrier property of the foam or of another filling material is increased accordingly.
A pressure accumulator in the form of a hydraulic accumulator known from WO 2013/056835 A1 has at least one elastomeric separating element, preferably in the form of a separating diaphragm or separating bladder, which divides the accumulator housing into at least two working chambers. One of the working chambers receives the one pressurizing medium, in particular in the form of a fluid. The other working chamber receives the pressurizing medium, in particular in the form of a working gas, such as nitrogen gas. A foam filling material is at least partially introduced into the accumulator housing, which filling material is delimited or surrounded by the separating element.
In order to define the storage capacity in the accumulator housing accordingly, the filling material, preferably of a polyurethane foam material, can be introduced as a solid form block into the accumulator with a predeterminable volume level. The filling material then creates a cavity at least inside the accumulator housing, which cavity can be filled with the respective working medium (fluid and/or gas). The filling material preferably is introduced in an already hardened, cellular structure as an open-pore finished foam form block into the cavity of the respective accumulator housing of a pressure accumulator.
Depending on the formation of the completely designed and produced foam-like filling material before its installation in the accumulator, a high storage capacity is obtained for the then modified accumulator. In addition, the stiffness of damping during operation of the accumulator can be correspondingly influenced. Furthermore, during operation of the accumulator, a homogenous temperature profile is obtained for the respective working media to be introduced and removed. The introduction of the already fully-foamed, in other words, hardened foam material and filling material, if appropriate, together with the accumulator bladder, into the accumulator nevertheless often presents issues. The free available installation openings of the respective accumulator housing are kept small for system-related reasons, such that avoiding damage to the foam and/or to the elastomer material of the separating layer during the introduction into the accumulator housing is not possible. In particular, dividing the accumulator housing into several segments in order to simplify the introduction of the foam is often necessary.
The segments must subsequently be joined together by a laser joint welding for example, which on the one hand involves intensive work and on the other hand compromises the homogeneity and thus the pressure stability of the wall of the accumulator housing. Because of the large number of work processes that this involves, the production of the known pressure accumulator solutions is time-intensive and thus cost-intensive. The costly production also prevents the design of the respective accumulator as a disposable component, which is a requirement of the rapidly modernizing market that is efficiency-oriented.